This invention relates to a sewing control system and a sewing control method for multiple-pattern sewing machines which employ digital codes as data for forming stitch patterns as well as a data processor for the control of sewing operation.
Heretofore, in a multiple-pattern sewing machine utilizing digital codes as data for automatically forming stitch patterns, a stitch pattern specified by means of a bight amount or a transverse needle shift and a feed amount or a longitudinal cloth feed has been formed in the following procedure, for example. That is, prepared as a stitch data in a static memory (ROM) is a digital code consisting of bight and feed data each in 5 bits which correspond to each individual stitch by 1:1. (Here, one stitch data is used for forming one stitch or one seam.) Then, scores of stitch data sets for forming a specified (or desired) stitch pattern are successively taken out of the ROM in accordance with the designation from a digital counter synchronized with the sewing action of the sewing machine. Thereupon, the sewing machine performs a cycle of sewing operation corresponding by 1:1 to each individual stitch data derived according to the designation by the digital counter, thereby forming the specified stitch pattern of a piece on cloth. In such sewing machine as described above, however, one stitch data is required for each stitch, so that a great number of digital codes are needed to form a complicated stitch pattern, or continuously to form a variety of stitch patterns. Consequently, in the prior art multiple-pattern sewing machines, the total number of data required may reach an enormous value, inevitably requiring a memory unit of large capacity.